Scientists discover 'transsexual gene' that makes men feel like women

Transsexual men who 'feel' female are likely to have an unusual version of a gene that affects the male sex hormone testosterone, a study has shown.

The discovery was made by scientists who examined DNA from 112 male-to-female transsexuals.

Israeli singer Dana International: Recent research shows that transsexuals like Dana are likely to have an unusual version of a gene that affects the hormone testosterone

In many cases there was a longer version of a gene known to modify the action of testosterone.

The alteration may 'under-masculinise' the brain during its development in the womb, the researchers believe.

Study leader Dr Vincent Harley, from Prince Henry's Institute in Clayton, Australia, said:'There is a social stigma that transsexualism is simply a lifestyle choice; however, our findings support a biological basis of how gender identity develops.

'As with all genetic association studies it will be important to replicate these findings in other populations.'

The findings are published in the journal Biological Psychiatry.

Professor Andrew Sinclair, from the University of Melbourne, said: 'This research suggests that extra long copies of the Androgen Receptor gene potentially affect testosterone function in the brains of male-to-female transsexuals.

'These defective copies of the AR gene could severely reduce normal testosterone levels, resulting in a more female-like brain. Consequently, male-to-female transsexuals might be expected to have a more feminised brain and are therefore likely to display a female gender identity.

'This supports the notion that transsexualism has a biological (genetic) basis rather than being due to psychosocial factors in early childhood.

'However, this finding does not explain all male-to-female transsexuals suggesting that multiple genetic factors are involved.'